Immature stages of Palearctic Mecinus species (Coleoptera, Curculionidae, Curculioninae): morphological characters diagnostic at genus and species levels Author Gosik, Rafal Department of Zoology and Nature Protection, Maria Curie-Sklodowska University, Akademicka 19, 20 - 033 Lublin, Poland Author Skuhrovec, Jiri Group Function of Invertebrate and Plant Biodiversity in Agro-Ecosystems, Crop Research Institute, Prague 6 - Ruzyne, Czech Republic https://orcid.org/0000-0002-7691-5990 jirislavskuhrovec@gmail.com Author Caldara, Roberto Center of Alpine Entomology, University of Milan, Via Celoria 2, 20133 Milan, Italy Author Tosevski, Ivo CABI, Rue des Grillons 1, 2800 Delemont, Switzerland & Institute for Plant Protection and Environment, Banatska 33, 11080, Zemun, Serbia text ZooKeys 2020 939 87 165 http://dx.doi.org/10.3897/zookeys.939.50612 journal article http://dx.doi.org/10.3897/zookeys.939.50612 1313-2970-939-87 B239701148884712880E1069C943AD33 DB6D50A55057576896F6AFDAE5BC9922 Mecinus sicardi Hustache, 1920 Material examined. 6 L3 larvae and 1 pupa, France, Provence-Alpes-Cote d'Azur , Alpes Maritimes, road Eze-La Turbie, 20.07.2014, on Antirrhinum latifolium Mill. stems, lgt. and det. R. Caldara. Accession numbers of sequenced specimen MN992007. Description of mature larva (Figures 25A-D , 26A-F ). Measurements (in mm). Body length: 2.71-3.75. Body width (abdominal segments I-II): 1.10-1.25. Head width: 0.60-0.65. Body (Figure 25A-D ) yellowish, slender. All thoracic segments almost equal in length. Abdominal segments I-V of almost equal length; segments VI-IX decreasing gradually to the terminal body part; segment X reduced to three anal lobes of those lateral are the largest, and dorsal the smallest (sometimes absent). Chaetotaxy weakly developed, setae capilliform, variable in length, yellow. Prothorax (Figure 25B ) with ten prns of unequal length (seven medium length, three short); two medium ps and one medium eus. Meso- and metathorax (Figure 25B ) with one very short prs , three pds , different in length ( pds1,3 very short, pds2 medium); one short as , three short ss , one medium long eps , one medium long ps and one medium eus. Pedal area with five pda , different in length. Abdominal segments I-VIII (Figure 25C, D ) with one short prs , four pds of different length ( pds1,2,4 short, pds3 medium; all pds on segments VI-VIII very long, equal in length) arranged along the posterior margin, one short and one medium ss , two medium eps , one medium ps , one medium lsts and two relatively long eus. Abdominal segment IX (Figure 25D ) with three very long ds , all located close to the posterior margin, one medium ps and two medium sts. Each of lateral anal lobe with two minute setae. Figure 25. Mecinus sicardi mature larva, habitus and chaetotaxy A habitus of the body and frontal view of the head B lateral view of thoracic segments C lateral view of abdominal segment I D lateral view of abdominal segments VII-X. Abbreviations: Th. I-III - number of thoracic segments, Abd. I-X - number of abominal segments, setae: as - alar, ds - dorsal, eps - epipleural, eus - eusternal, lsts - laterosternal, pda - pedal, pds - postdorsal, prns - pronotal, prs - prodorsal, ps - pleural, ss - spiracular, sts - sternal, ts - terminal. Head capsule (Figures 25A , 26A-F ) yellow, distinctly narrowed bilaterally. Des1-3,5 equal in length, des4 twice shorter than other des. Fs1,4,5 long, equal in length, fs3 medium. Les1 and les2 medium, equal in length; two ves short; four pes spine-like (Figure 26A ). Two stemmata of different size. Antennae (Figure 26B ) with sensorium (Se) conical, twice as long as wide, located medially, and three sensilla of different types: one sa and two sb. Clypeus (Figure 26C ) trapezium-shaped, anterior margin slightly concave; two medium cls , located posteromedially; clss clearly visible. Labrum (Figure 26C ) close to semi-circular, anterior margin sinuate; lrs1-3 almost equal in length. Epipharynx (Figure 26D ) with three rod-shaped als of almost equal length; two medium, finger-like ams ; one medium, finger-like mes ; surface smooth; labral rods short and relatively wide. Mandibles (Figure 26E ) conical, wide, with small protuberance in the middle of the cutting edge; both mds capilliform, medium, equal in length, placed transversely. Maxilla (Figure 26F ) with one stps and two pfs of equal length; mbs short; mala with six rod-like dms of almost equal size, five vms different in size. Maxillary palpi: basal palpomere slightly wider than distal, both of almost equal length. Prelabium (Figure 26F ) cup-like with one long prms ; ligula with three minute ligs ; premental sclerite clearly visible, cup-shaped, posterior extension with acute apex. Labial palpi two-segmented; basal palpomere distinctly wider than distal, both of almost equal length. Postlabium (Figure 26F ) with three pms ; pms1 and pms3 short, pms2 three times as long as pms1 . Figure 26. Mecinus sicardi mature larva, head and mouth parts A head, frontal view B antenna C clypeus and labrum, dorsal view D epipharynx E left mandible F maxillolabial complex, ventral aspect. Abbreviations: at - antenna, clss - clypeal sensorium, des - dorsal epicranial, lr - labral rods, sa - sensillum ampullaceum, sb - sensillum basiconicum, Se - sensorium, st - stemmata, setae: als - anterolateral, ams - anteromedial, cls - clypeal, dms - dorsal malar, fs - frontal, ligs - ligular, lrs - labral, ls - lateral epicranial, mbs - malar basiventral, mds - mandibular, mes - median, mxps - maxillary palp, pes - postepicranial, ves - ventral, pfs - palpiferal, pms - postlabial, prms - prelabial, stps - stipal, vms - ventral malar. Description of pupa (Figure 27A-C ). Measurements (in mm). Head width: 0.60-0.70. Body width: 1.75-2.00. Body length: 3.75-4.50. Body elongated, white. Rostrum moderately slender, about 3.5 times as long as wide, reaching up to mesocoxae. Antennae elongated. Pronotum 1.8 times as wide as long. Urogomphi (ur) slender, conical, with sclerotised apex, both directed outside, distinctly reaching outline of the body (Figure 27A-C ). Chaetotaxy setae medium or elongated. Head with one vs , two sos and two os . Rostrum with one pas . Setae on head and rostrum straight, as long as those on prothorax (Figure 27A ). Pronotum with two as , two sls , two ls , one ds and four pls. Dorsal parts of meso- and metathorax with three setae equal in length setae placed medially. Abdominal segments I-VIII with three very short setae ventrally and two setae laterally. Dorsal parts of abdominal segments I-VII with six setae growing gradually from segment I to VII ( d1 placed anteromedially, d2-5 placed posteromedially, d6 posterolaterally); segment VIII with five elongated setae dorsally. Abdominal segment IX with two micro-setae ventrally. Figure 27. Mecinus sicardi pupa habitus and chaetotaxy A ventral view B lateral view C dorsal view. Abbreviations: Th. I-III - number of thoracic segments, Abd. I-IX - number of abdominal segments, ur - urogomphi, setae: as - apical, d - dorsal, ds - discal, fes - femoral, l , ls - lateral, os - orbital, sls - postantennal, pls - posterolateral, rs - rostral, sls - superlateral, sos - superorbital, vs - vertical. Biological notes. The host plant of this species, at least in Cote d'Azur , is Antirrhinum latifolium Mill. As reported by Caldara and Fogato (2013) , larvae feed on the larger stems of the plant and dig tunnels, causing at most very small lateral deformations. They pupate in summer, and adults stay inside the plant until the spring of the following year. Before pupation, however, the mature larvae leave the main tunnel, which runs longitudinally, and produce a small oblique tunnel that ends just in proximity of the external cuticle of the stem. Therefore, when leaving their cells, adults have only to bore a thin layer, although in the meantime, the plant has become dry and hard. Remarks and comparative notes. The adults of this rare species, with a narrow range of distribution - in fact, it is known in a few localities of southeastern Spain, eastern and southern France, and north-western Italy - differ from the other species studied here by the black elytra instead of blue. Due to this character, this species may be superficially confused with M. pyraster , from which it is easily distinguishable by the elytral vestiture composed of scales that are uniformly arranged and are all recumbent. The rostrum (in dorsal view) is distinctly wider, and the pronotum has sides slightly more rounded and is usually widest towards the middle. Finally, ventrite 5 of the male lacks a tuft of hairs, and the shape of the penis is different. The larvae of this species differ from the others of the group by the abdominal segments I-VIII with two ss (instead of three) and asperities covering only the posterior part of postlabium, whereas pupae differ in having the rostrum with only one sls (instead of two) and without rs and the pronotum with four pls (instead of three).